Electrode-holder for search-lights.



E. A. SPERRY.

ELECTRODE HOLDER FOR SEARCH L IGHTS.

APPLICATION FILED MAR. 13. 1918.

1,282,133. v Patented 0012.22, 1918;

3 SHEETS-SHEET I,

7 m i I l f IIVVENTOR Hum/15pm E. A. SPERRY.

ELECTRODE HOLDER FOR SEARCH LIGHTS.

' nrucmon FILED MAR-13.1918.

" Patented Oct. 22, 1918.

3 SHEETS-SHEET 2- E. A. SPERRY.

ELECTRODE HOLDER FOR SEARCH LIGHTS.

APPLICATION FILED MAR. I3. 1918.

1,282,133. Patented 00t.22,19118.

3 SHEETSSHEET 3.

$ ,15 mum/rah [741m {7 Emmy B w $411M ATTOR Y ELMER A. SPERRY. OF BROOKLYN, NEW YORK.

ELECTRODE-HOLDER FOR SEARCH-LIGHTS.

Specification of Letters Patent.

Patented Oct. 22, 1918.

I Original application filed April 16, 1915, Serial No. 21,661. Divided and this application filed March 13,

1918. Serial No. 222.208.

apparatus therefor so that a greatly increased candle-powder is obtained. While I propose to use in my searchlight the very latest developments in arc-sustaining and light emitting materials, such as thin, cored, flaming arc carbons, my invention does not lie in the electrodes per se but in the combination of such electrodes with my improved apparatus for burning the same.

For operating the electrodes of searchlights at the high current density and with the heavy currents Which I propose to use, I have found the existing types of holders and other mechanical features of the standard searchlight utterly unsuited. The main object of my invention is to devise a practicable means by which the heavy current is handled within the lamp without loss or damage to the electrodes and whereby the "operating conditions of the are are improved, so that continuous, efficient burning may be secured. I have found that the principal causes of lack of brilliancy and loss of candle powerv in such lights are first, the loss of the heat of the crater by conduction and radiation; second, the vaporization and oxidation of the carbon farther back of the crater of the positive carbon than a predetermined amount; third, loss of electrical energy throu h the resistance of the carbon,

and fourth, t e spreading of the arc to the sides of the carbon, which isforthe most part due to said vaporization and oxidation. For. searchlights, the only effective light is that which issues from the crater itself or the immediate vicinity thereof. In other words, high intrinsic brilliancy at the crater is the condition most desired. The intrinsic brilliancy may be said to depend on at least four important factorsfirst, the electrical energy supplied to the electrode; second, the reduction of the loss due to electrical resistance within the electrode; third, the confining of the arc tothe immediate vicinity of the crater, and fourth, the elimination as far as possible of thel'oss of heat energy due to conduction of heat back through the electrode.

It is not often realized that of the energy converted to heat at the crater only 40% is radiated (as crater emanations) from the crater as heat and light, while the remaining is lost by conduction back through the carbon whence it is dissipated at lower tern perature by heat radiation and convection due to aifcurrents. It is the purpose of this invention to increase the per cent. ofthe energy converted into useful radiations at the crater, to decrease the conduction and convection losses and to reduce arcing from the sides of the electrode, thus materially increasing the intrinsic brilliancy. To accomplish this I run the positive carbon at high current density, surround it for some distance back of the crater with a refractory sleeve adapted to shield or insulate the electrode from air currents, and introduce current close to the are which last is rendered possible by cooling the electrode between the point of current introduction and said sleeve. The sleeve'need not and preferably does not, however, extend to the end of the electrode but stops a short distance from it so that a limited but very desirable spindling of the electrode may take place."

According to the preferred form of .my invention the said sleeve, the cooling means and the current introducing means all form a part of the electrode holder, within which the electrode is both fed and rotated.

Another object of my invention is to improve the general construction of searchlights. Further objects will appear as the invention is described in detail.

In the drawings in which are illustrated several forms that the invention may as- Fig. 6 is a detail showing the method of applying pressure to the brushes in the positive holder;

Fig. 7 is a rear elevation of the positive holder;

Fig. 8 is a detail thereof;

Fig. 9 is an elevation of the interior of the searchlight drum;

Fig. 10 isadetail showing themanner in which the box supporting the lamp mechanism is supported within the drum;

Fig. 11 is a section on line 1111 of Fig. 2;

Fig. 12 is a cross section of one of the standards supporting the holders, on line 12*12, Fig. 1. e

In Fig. 9, 1 represents the reflector or projector of the searchlight 2, while the drum is shown at 3 and the front window at 4. The front window is preferably made so that it may be swung open on hinges 5 or may otherwise be removed to permit the withdrawing of' the lamp mechanism. The window is shown as provided with an opening 6 near the center thereof which is reinforced by a thimble 7 through which the positive trol box together with the electrode holders may be readily removed. IVhile in Fig. 9 the holders are shown as axially positioned, this arrangement may be obviously varied within fairly wide limits without affecting the operation of the invention described and claimed herein.

Instead of securing the electrodes to their holders and moving the holders bodily to effect the feeding of the electrodes, as has heretofore been the standard practice in searchlights, I prefer to make at least one and preferably both holders stationary during the normal burning of the arc and to feed the electrodes through their holders and also to rotate at least one of the electrodes within the holder.

The holders 12 and 13 for the electrodes are preferably supported from the control box 11 on hollow legs or standards 15 and 16 which preferably also serve to introduce a supply of cooling fluid to the holders, as hereinafter described, and to lead in current to the electrodes. Pairs of standards 15 and 15 and-16 and 16" are shown as provided for each holder. The holder 13 "preferably comprises a metallic body portion 90 which is secured to the upper ends of the legs 16 and 16. The said holder is provided with quartz or thelike and is shown as extending fairly close to the arcing face 18 of the electrode, but spaced a predetermineddistance therefrom. The sleeve preferably forms an extension from the holder, being clamped thereto at its forward end, as herelnafter explained. This sleeve performs several important functions, among which is that it maintains that portion of the electrode which it surrounds at white incandescence by reducing radiation and shielding it from heat abstracting air currents. It also shields the electrode from vaporization and oxidation, which at this temperature would cause too great spindling of the electrode. The metallic holder also assists in performing the last named function, being joined to the sleeve. The action of the arc flame and heat on the projecting portion of the electrode is to cause it to taper to a more or less degree and hence to reduce the size of the light source, orin other words, the size of the positive crater. As is well known in searchlights, the smaller the light source secured the greater the intensity and brilliancy of the beam, so that by permitting this predetermined tapering to occur the size of the light source is appreciably reduced and the efliciency of the light increased for a given size of the positive electrode. By feeding the electrode through the holder, the length of the tapering section is kept constant, whilethe rotation of the electrode causes equal spindling on all sides.

. trode- Back of the sleeve the holder is formed in such manner as to permit the circulation therethrough or thereover of a cooling fluid such as air and to dissipate heat at a rapid rate thereto. For this purpose the holder is shown as provided with a plurality of heatradiating fins or ribs 19 having cut-away portions 2021 adjacent their tops and'bot toms to permit the free intake and egress of the air. The holder preferably tapers toward the arc. The ribs so. provided are preferably entirely. inclosed an outer member air escapes in an upward direction. The air coming up through the hollow legs 15 and 16" enters the holder through the openings 23 and 24: and passes from the body of the holder out toward the ribs through opening or openings25. The sleeve 17 is fastened to the holder and shield 22 by an air-tight joint 26 so that no gas or air is allowed to escape toward the arc. By employing an intensive cooling means as described for .the electrode holder,"I am enabled to introduce current to the electrode much closer to the arc than otherwise, since according to my invention the electrode in the drum is run at such high current density and such enormous crater temperatures are reached that the heat of an uncooled electrode near the arc would be suilicient to seriously damage any brushes employed to introduce current tothe'electrode. By my invention I am also enabled to greatly reduce the size of the electrode holder, which "would otherwise be necessary to dissipate the large amount of heat generated. I. thereby gain the advantage of compactness and also cut off a minimum amount of light from the searchlight beam. This effect is further increased by tapering the ribs toward the are as described. By employing this cooling :means I am enabled to place the brushes 26 on the holder immediately back of the cooling ribs, thereby reducing the resistance lossesin the electrode and securing a compact structure.

One construction for the brushes is as follows: The holder is proi ided near its top with an oval or -elongated aperture at 27 leading down to the electrode. In the said aperture is fitted a block 28 having a plurality of holes 29 therein. In the said holes are fitted the brushes 26, proper. Each brush is shown asprovided with a detachable wearing block 30 for making contact with the rotating electrode. plied to the brushes by means of a pair of springs 31 which act through a system of equalizing links 32 upon the ends of cross pieces 33, 33 and 33 mounted in slots at the top of the blocks. The equalizing links (see Fig. 6) preferably comprise a pair of links 84: and 35, each of which has its inner end supported on the central piece 33 and extends in opposite directions to the corresponding outer piece 33 or 33". The springs 31 are secured to the center of the equalizing bar 37 which has its ends supported by links 3i and 35, the points of connection being such that 'equal pressure is exerted on all brushes.

As above stated I prefer to rotate and feed the positive electrode through its holder.

ressfire is ap- While the specific mechanism for effecting this purpose forms no part of this invention, being claimed in my copending application for improvements in searchlights, Serial No. 21,661, filed April 16, 1915, of which this present case is a division, I have illustrated and will briefly describe the mechanism more completely set forth and claimed in said application.

Journaled upon said body portion 90 is a rotatable member 40 upon which is mounted a worm wheel 41. Said wheel is rotated by means of a worm 42 rotated from the shaft 43 extending without the drum through gearsd'andjli-ii. Pivotally mounted on the face of said member or gear is a pair of brackets 46 and i7 which are normally pulled together by a spring i8. The brackets carry the feed rollers 49 and 50 on the electrode. The rollers are rotated by means of worm wheel 51 mounted upon the'shaft of the roller 50 and worm 52 on theshaft 53 of the gear or star wheel 5%. Motion may be transmitted to the feed roller 49 through spur gears 55 and 56 mounted on the shafts of the rollers respectively. It may be readily seen that as the member l0 revolves, the feed rollers and cars will be carried around with it and there y rotate the electrode. and also that the star wheel 54 will be revolved in a planetary fashion about the electrode but will not be rotated upon its own axis. To effect the feed of the electrode a stop pin 57 is provided which may be adjusted into or out of the path of the star wheel. The position of the stop may be automatically controlled by the position of the arcing face of the electrode as disclosed in said other application; or it may be adjusted by hand. The automatic means is diagrammatically represented in Fig. 9 by an electro-magnet 60 which operates to draw the pivoted armature 61 against the action of the spring 62 thereby raising the lever 63 through the link 64: and also the rod 65 of which the said stop means is an extension.

It will be readily seen that upon excitation of the magnet 60, which may be effected in any manner such as by the voltage across the are or the position of the electrode with respect to a thermostat, the stop may be pushed into the path of the star wheel and the feeding of the electrode effected; and also that the stop may be pushed out of the path of the star wheel by the action of spring 62 so that the feeding will stop. It will also be apparent. that the stop ma be placed in the path of the star wheel by raising the handle 63 or by an adjustment of the cam 64C The construction of the negative holder 12 as shown is similar to that of the positive lIiO lit)

to rotate the negative electrode; hence the feeding rollers 61' and 62 may be rotated directly from the drive shaft 63' as by means of a worm on the drive shaft, and worm wheel 65 on the shaft of the roller (32. Gears 66 and 67 transmit motion to the upper roller as before. An added change is made possible in the negative holder due to the different conditions presented in the two cases. IVith the positive electrode the greatest amount of heat seems to be generated at the crater face and is carried back by conduction. The problem of introducing current close to the arcing face of the positive electrode therefore resolves itself mainly into the dissipation of the crater heat far enough from the crater so as not to materially lessen the crater temperature. It is partly to maintain this crater temperature that the refractory sleeve is employed. With the negative electrode, on the other hand, which is much smaller in diameter, the heating effect is mainly due to the resistance of the electrode, the current density being sufficient to maintain it at white heat. It is a matter therefore of even more importance in the case of the negative electrode to introduce the current very close to the arcing face and to keep the brushes as cool as possible. Accordingly, the spring pressed brushes 107 which are employed for insuring good contact with the electrode are positioned forwardly of a portion of the cooling ribs 68, another portion of the cooling ribs 69 being placed in front of the brushes and in contact with the electrode. A protective sleeve 70 may also be used for the negative electrode for the purpose of preventing too rapid spindling thereof. The negative holder is shown as made up of a plurality of detachable sections 71, 72, and 7 3 so as to give ready access to the brushes. In order that the negative electrode 7 1 may be inserted in the holder the latter is pivotally secured to the legs 15 and 15 '(see Fig. 11) by means of a bolt on which it may be swung'upwardly. Besides placing the holder in a position in which the electrode may be inserted, this upward movement will disengage the worm wheel 65 from the worm 16% thus allowing the feed rollers to rotate easily when inserting the carbon.

\Vhile neither holder is moved for bringing about the feeding of the carbons, I prefer to move. the negative holder substantially axially for striking the arc. To permit of this. I pivotally mount the legs 15 on pivot 70, located outside of the searchlight. and providemeans for oscillating the holder about this pivot to strike the are as explained in said other application, the are striking magnet being at 73.

In the control box is mounted a single motor 77, which furnishes power for all of motor prefei ably by coupling it directly thereto. The supply of air may be drawn through holes 79 in the box and is forced by the blower up through legs 15 and 16, a

cross pipe 80 being provided to lead the air across to legs 15 which are hinged thereto at point 81. Motor 77 also supplies power for rotating and feeding the positive carbon through the long shaft 43, which may be rotated from the motor shaft by worm gearing 82. In order that the least amount of shadow may be thrown by the transmission mechanism both shafts -13 and 65 are placed in line with one of legs 16 or 16. Said legs are preferably placed in line with and parallel to legs 15. \Vithin box 11 is also placed the mechanism for feeding the negative carbon as described in said other application.

Shaft 63" is provided with a universal joint 102, and" slidable coupling 103, in! order to permit oscillation of holder 12 about pivot 70. Also said shaft should be mounted in line with one'of legs 15 or 15.

On account of the intense heat of my type of arc lamp, and the consequent danger of damaging the reflector, and also on account of the fumes generated by a flaming are which condense on and dim the reflector, I prefer to equip my searohlight with an exhaust fan 201, at the exhaust opening 201 which may be at the top of thecasing 2 (Fig. 9). For rotating the fan; a slender squared shaft 202 may beemployed, which normally fits loosely in a squared opening 92 in worm 12 (Fig. 8). Sleeves 203 are provided in the bearings 201, 205 and 206 for the shaft, so as to permit rotation thereof. A gear 207 is slidably but non-rotatably mounted on the shaft 202, and drives the fan 201 through pinion 208. Shaft 202 may be moved longitudinally by means of finger piece 209, so as to. disengage it from shaft 43 when it is desired to remove the holder 13.

In Fig. 5, a slightly modified form of holder 13 is shown, the principal difference being in the method of securing the refractory sleeve 17 to the holder. In this case the sleeve 17 is made with a flaring end 214, which is clamped between the conical end of holder 13, and the cone-shaped shield 22', said shield being drawn into close engagement therewith by a spring 215. Packing rings 216 may be provided to insure a tight fit. Also in this figure, the shield 20 is shown as made up of a metallic base 218.

lows: as soon as the current is turned on, and

adjusted through any means, magnet 73 will strike the arc, as will be readily apparent.

At the same time the motor 77 is started up,

and all the various functions performed thereby are set into motion. The cooling medium is forced up the legs 15 and 16 and into intimate contact with the holders 12 and 13 and rotating mechanism 40 revolves carbon 8 and also feeds it under the control of the mechanism shown in Fig. 7, which is responsive to the changes of the position of the positive crater. At the same time the exhaust fan 201 is started, which aids in ventilating and cooling the interior of the drum by assisting the blower 78 in forcing air through the drum. The streams of air issuing from slots 19 also perform an im portant ventilating function in that they entrain the fumes from the arc and carry them directly to the opening 201.

In accordance with the provisions of the patent statutes, I have herein described the principle of operation of my invention, together with the apparatus, which I now consider to represent the best embodiment thereof, but I desire to have it understood that the apparatus shown is only illustrative and that the invention can be carried out by other means. Also, while it is designed to use the various features and elements in the combination and relations described, some of these may be altered and others omitted without interfering with the more general results outlined,and the invention extends to such use. I

Having described my invention, What I claim and desire to secure by Letters Patent is:

1. In a Searchlight, an electrode holder comprising means for introducting current to the electrode, a metallic portion adapted to closely fit the electrode between the point at which current is introduced to the electrode and the are, a plurality of heat radiating ribs on said portion, and means for intensively cooling said portion by circulating a cooling medium thereover.

2. In a searchlight, means for confining the consumption of the positive electrode to the region of the tip, comprising a metallic jacket adapted to fit the electrode near its end, means on said jacket for dissipating coming into direct contact with the electrode.

3.In a Searchlight, an electrode holder comprising a metallic member adapted to fit the electrode, a plurality of heat radiating ribs on the forward portion thereof a shield for inclosing said ribs, means forlntroducing a supply of cooling gas within said shield, and means permitting the escape of said gas at the top of said shield.

I. In a searchlight, a hollow casing adapted to surroundtheelectrode adjacent the are, said casing being closed at its for- Ward end, means for causing'air to flow therethrough, means for feeding the electrode through the casing, and a refractory, heat insulating sleeve, extending forwardly from the casing to within a predetermined distance of the electrode tip.

5. The herein described method of operating arc lights for projectors which con' sists in operating the positive electrode at high current density and excluding all gases from the end of the electrode up to a point immediately adjacent the arc, and in vigorously abstracting heat from said end by circulating a cooling medium therearound.

6. The method of operating arc lights for projectors, which consists in operating an electrode wat high current density, introducing the current supply close to the arc, and in abstracting heat from the electrode between the arc and the point of application of the current by the circulation of a cooling medium. n

7. In an are light, the combination-With a positive electrode, of a jacket adapted to abstract heat from the electrode, and means on said jacket causing rotation and axial movement of the electrode within the jacket.

8. In a searchlight, means for confining the are to the tip of an electrode, comprising a heat abstracting casing adapted to surround the electrode adjacent the arc and to closely fit the same throughout the greater portion of its length, and means for supplying and circulating a cooling fluid within said casing.

9. In a Searchlight, the combination with a drum, an electrode holder positioned therein having an air passage therethrough, an air duct leading from a point without the drum to said holder, and means for circulating air through said holder and duct.

10. In a Searchlight, the combinationwith a drum, an electrode holder positioned therein having an air passage therethrough, an air. duct leading from a point without the drum to said holder, and means for causing a diflerence in pressure to exist at the inlet of the duct from that at the outlet of the with adrum, an electrode holder positioned therein having an air passage therethrough, an air duct leading from a point without the drum to said holder, and means for causing a difference in pressure to exist at the inlet of the duct from that at the outlet of the holder whereby air is caused to flow from without the drum through the duct and.

holder.

12. In a searchlight, the combination with a drum, and an electrode holder movably located therein, means for cooling said holder comprising a duct connecting said holder and a point without the drum, an air circulating device connected to said duct, the connections being such that air may besupplied thereto irrespective of the movements of the holder.

13. In a Searchlight, the combination with a drum and an electrode holder pivotally located therein, means for cooling said holder comprising a duct connecting said holder and a point without the drum, an air circulating device connected to said duct and a joint in the connections between the device and the duct.

14. In a Searchlight, the combination with a drum and an electrode holder movably located therein, a hollow support for said holder, a pivot therefor having a passage therethrough, and means for causing a circulation of a cooling medium through said duct to said holder.

15. In a searchlight, the combination with the drum and electrode holders, of means for ventilating the drum comprising an inlet air duct leading from a point without the drum and having an outlet adjacent an electrode holder, and means for causing air to pass through said duct, whereby a current of air is produced leading away from said holder which entrains the fumes from the arc.

16. An electrode holder for a positive electrode adapted to be operated at high current density comprising a forward heat resistive and insulating sleeve, adapted to extend close to the arc, a metallic heat abstracting section, means for circulating cooling air over said section, and means for introducin' current to the electrode located adjacent sai section.

17. An electrode holder for a ositive electrode adapted to be operated at igh current density comprising a forward heat resistive and insulating sleeve adapted to extend close to the arc, a metallic heat abstracting section, means for irculating air over said section, and means also located adjacent said section for feeding the electrode through the holder.

18. In a searchlight, an electrode holder comprising a metallic member adapted to fit the electrode, a plurality of heat radiating ribs on the forward portion thereof, an inclosure for said ribs, and means for introducing a supply of air within said inclosure, sa d inclosure being provided with an opening to pernnt the escape of said air.

19. In a Searchlight, an electrode holder including a hollow portion having an interior and exterior wall and a central aperture through the interior wall for an electrode, ribs on said interior wall, and means for introducing a supply of air within said portion.

20. In a Searchlight, an electrode holder including a hollow portion having an interior and exterior wall and a central aperture through the interior wall for an electrode, ribs on said interior wall tapering-in diameter toward the arc, an opening in said exteripr wall tapering away from the arc, and means for introducing a supply of air within said portion.

21. In a searchlight, a metallic jacket adapted to fit the electrode adjacent its end, heat dissipating ribs thereon,'a forwardly extending refractory and insulating sleeve, and means for blowing air over said ribs.

22. Ina Searchlight, a metallic jacket adapted to fit the electrode adjacent its end, heat dissipating ribs thereon, a forwardly extending, refractory and insulating sleeve, means for blowing air over said ribs, and means for preventing said air from disturbing the arc.

23. The herein described method of producing a high power are between carbonaceous electrodes which consists in introducing current to the positive electrode at a comparatively short distance from its arcing end, in cooling that portion of the electrode immediately adjacent said point of current introduction and in preventing the loss of heat from and the oxidation of said electrode within a zone adjacent said arcing end and between it and said cooled portion.

24:. The herein described method of producing a high power are between carbonaceous electrodes which consists in introducing current to the positive electrode at a comparatively short distance from its arcing end, in cooling that portion of the electrode immediately adjacent said point of current introduction and in preventing the loss of heat from and the oxidation of said electrode within a zone adjacent but spaced from said arcing end and between it and said cooled portion.

25. The herein described method of operating arc lights for projectors, which consists in operating a carbonaceous electrode at high current density, jacketing the electrode between the point where it receives current and thearc, circulating a cooling medium therearound and causing relative movement between the jacket and the electrode.

26. In a Searchlight, an electrode holder including a hollow portion having an interior and exterior wall and a central aper- .of comparatively holder, said support ture through the interior wall for an electrode, ribs on said interior wall tapering in diameter toward the arc, and means for lntroducing a supply of air within said portion.

27. In asearchlight, an electrode holder means on the holder for feeding an electrode therethrough and theholder whichare located between the arc and said feeding means and which taper toward the arc.

' 28. In a Searchlight, a drum, electrodes within said drum, said drumbeing provided with an exhaust port and means for introducing into said drum a current of air directed away from the are but toward said exhaust port.

29. A Searchlight comprising a drum, an electrode, a hollow support for said electrode and means for injecting outside air into said drum through said support.

30. A Searchlight comprising a drum, an electrode, an electrode holder provided with an air passage, a hollow support for said holder and means for injecting outside .air into said drum through said support-and holder. v

31. In asearchlight, the combination with a drum, an electrode holder positioned there in, means Without the drum for furnishing a continuous supply of gaseous cooling medium to said holder, and a support for said also constituting a duct for leading the coolingmedium from said means to said holder.

32. In a searchlight, the combination with small diameter including heat dissipating means 011 a pair of -arc said chamber, and a motor signature.

a pair of electrode holders, driven means connected to each holder for feeding the electrodes, an air circulating device for cooling either holder, a source of power, and means connecting said power source with each of said driven means and with said device.

34. In a Searchlight, an electrode holder comprising a metallic portion adapted to closely fit the electrode between the point at which current is-introduced to the electrode and the are, a chamber around said portion,

means for feeding the electrode through the holder, a blower for circulatin air through or operating both said blower and said feeding means.

35. In a Searchlight, the combination with an electrode holder, of driven means mounted on the holder for both feeding and rotating the electrode through and within the holder, an air circulating device for cooling said holder, a source of power and means 'cOnnecting said power source with said means and said device.

In testimony whereof I have afiixed my ELMER A. SPERRY. 

